Epstein-Barr Virus (EBV) is a tumor virus that causes lymphdmas and carcinomas in approximately 100,000 people each year. We have developed and applied genetic analyses of EBV's transforming genes with this grant's prior support focusing on EBV's latent membrane protein 1 (LMP1) in infected B- lymphocytes. These analyses identified a phenotype and cellular genes induced rapidly by LMPVs signaling. We propose to extend our genetic analysis to dissect further transforming functions of LMP1, Epstein-Barr Nuclear Antigen 1 (EBNA1), and EBV's microRNAs (miRNAs) by identifying phenotypes they induce and cellular genes they regulate. These viral transforming genes are all implicated in maintaining tumor phenotypes in some or all of EBV-associated tumors. Our proposed genetic analyses will help to elucidate how these viral transforming genes contribute to tumor maintenance. We shall also extend our genetic analyses of these viral genes to dissect their functions in infected epithelial cells. EBV causes more carcinomas than lymphomas, but studies in normal epithelial cells formerly were intractable. These cells are now amenable to infection allowing us to characterize EBV's transforming genes in them. EBV functions differently in B-lymphocytes and epithelial cells. We hypothesize that these viral transforming genes regulate different cellular genes in B-lymphocytes and epithelial cells to mediate EBV's different oncogenic contributions. The proposed genetic analysis of EBV's transforming genes will help to identify their^contributionsto maintaining EBV-associated lymphomas and carcinomas. An understanding of viral contributions to tumor maintenance will allow development of specific anti-viral, anti-tumor therapies.